A circuit and method for providing a periodic clock signal, such as a high frequency clock signal. In one example, the circuit may include a phase locked loop circuit having a voltage controlled oscillator, the voltage controlled oscillator having a voltage input, a calibration input, and a clock signal output; and a logic circuit for dynamically calibrating an operating frequency of the phase locked loop during operation of the phase locked loop. In one embodiment, the logic circuit may compare an input voltage into the voltage controlled oscillator against a reference voltage, and if the input voltage is lower than the reference voltage, the logic circuit decreases the operating frequency of the phase locked loop circuit. The logic circuit may compare an input voltage into the voltage controlled oscillator against a reference voltage, and if the input voltage is higher than the reference voltage, the logic circuit increases the operating frequency of the phase locked loop circuit.